1. Technical Field
The present disclosure relates to a device for use in orthopedic surgeries and, more specifically, to axial spinal rod connectors that are axially adjustable.
2. Discussion of Related Art
The human spinal column is a highly complex structure. It includes twenty-four discrete bones, known as vertebrae, coupled sequentially to one another to house and protect critical elements of the nervous system. The cervical portion of the spine, which includes the neck of the spine up to the base of the skull, includes the first seven vertebrae.
Disease, the effects of aging, or physical trauma resulting in damage to the spine has been treated in many instances by fixation or stabilization of the affected vertebra. A wide variety of spinal fixation apparatuses have been employed in surgical procedures for correcting spinal injuries and the effects of spinal diseases. Many of these apparatuses commonly use a pair of longitudinal rods running in a relatively parallel relationship to each other. Additional fixation methods are also employed that mate with the spinal rod to provide additional points of fixation. These include, but are not limited to, head to head connectors, rod to rod transverse connectors, hooks and axial rod to rod connectors.
Axial spinal rod to rod connectors are often used in subsequent surgeries when there is existing hardware already implanted in the patient. The axial spinal rod connector is used to continue the spinal rod construct from the original hardware to the new hardware that is implanted. The axial spinal rod connector provides support for the new hardware and helps to orient it appropriately with the existing hardware. In addition, an axial spinal rod connector may be used as a bridge between sections of hardware if there are two separate, non-adjacent regions that require instrumentation. Sometimes the upper thoracic region requires instrumentation as well as the lumbar region and the axial spinal rod connector may be used to connect the spinal rod from these two regions. The axial spinal rod connectors are made in various lengths, preferably 20-90 mm in length, and also may accept various spinal rod diameters, shapes and materials, for example if a smaller 4.5 mm spinal rod is used in the thoracic region and a 5.5 mm spinal rod is used in the lumbar region, the axial spinal rod connector can accommodate both of these sized spinal rods and connect with both spinal rods.
A need exists for an axial spinal rod connector that is longitudinally adjustable for discrete and precise movement of the spinal rod in set increments which affords control over the axial tension on the spinal rod between spinal constructs.